Intraoral appliance for sound transmission via bone conduction

ABSTRACT

An intra-oral appliance for transmitting sound via bone conduction and optimized for comfort, safety, speech intelligibility, eating and drinking and extended wear by the user including an actuator to provide bone conduction sound transmission; a transceiver coupled to the actuator to cause the actuator to generate sound; and a first chamber containing the actuator and the transceiver, said first chamber adapted to be coupled to one or more teeth of the user.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/607,114 filed May 26, 2017, which is a continuation of U.S. patentapplication Ser. No. 15/209,570 filed Jul. 13, 2016 (now U.S. Pat. No.9,781,525 issued Oct. 3, 2017), which is a continuation of U.S. patentapplication Ser. No. 13/872,965 filed Apr. 29, 2013 (now U.S. Pat. No.9,398,370 issued Jul. 19, 2016), which is a continuation of U.S. patentapplication Ser. No. 12/878,276 filed Sep. 9, 2010 (now U.S. Pat. No.8,433,082 issued Apr. 30, 2013), which claims the benefit of priority toU.S. Patent Application No. 61/248,262 filed Oct. 2, 2009, each of whichis incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to methods and apparatuses for thetransmission of sound via bone conduction by means of an intraoralappliance.

BACKGROUND OF THE INVENTION

Recent advances in miniaturized electronics and materials science haveresulted in the creation of intraoral appliances incorporating actuatingtransducers that facilitate the transmission of sound using theprincipal of bone conduction. Such IOAs have been described for use in avariety of applications including the treatment of subjects withunilateral hearing loss or single-sided deafness (see, e.g., U.S. patentapplication Ser. No. 11/754,823), treating subjects suffering fromtinnitus (see, e.g., U.S. patent application Ser. No. 11/845,712),facilitating two-way communications (see, e.g., U.S. patent applicationSer. Nos. 11/952,780 and 12/175,240), and consumer electronics productssuch as digital audio players (see, e.g., U.S. patent application Ser.No. 12/464,310). Although the aforementioned IOAs have been shown toaddress disparate problems and needs, they have in common the need forthe user to wear the IOA for prolonged periods of time. Thisnecessitates that the IOA be designed so that it is optimized forcomfort in the mouth of the user. Such an IOA is described herein.

SUMMARY OF THE INVENTION

In one embodiment, an intra-oral appliance is provided that is optimizedfor user comfort to facilitate extended wear of the appliance andincludes an actuator to provide bone conduction sound transmission; atransceiver coupled to the actuator to cause the actuator to generatesound; and a first chamber containing the actuator and the transceiver,said first chamber adapted to be coupled to one or more teeth.

Implementations of the above aspect may include one or more of thefollowing.

An actuator driver or amplifier can be connected to the actuator. Asecond chamber can be used to house a power source to drive the actuatorand the transceiver. A bridge can connect the first and second chambers.The bridge can have electrical cabling or an antenna embedded in thebridge. The bridge can be a wired frame, a polymeric material, or acombination of polymeric material and a wired frame. A mass can beconnected to the actuator. The mass can be a weight such as tungsten ora suitable module with a mass such as a battery or an electronicsmodule. The actuator can be a piezoelectric transducer. Theconfiguration of the actuator can be a rectangular or cantilever beambender configuration. One or more ceramic or alumina stands can connectthe actuator to other components. A compressible material can surroundthe actuator. A non compressible material can cover the actuator and thecompressible material. A rechargeable power source can power thetransceiver and the actuator. An inductive charger can recharge thebattery. The chamber can be a custom oral device. A pre-built housingcan be provided for the mass. The pre-built housing can have an arm andone or more bottom contacts, the arm and the contacts adapted to bias amass against a tooth. A microphone can be connected to the transceiver,the microphone being positioned intraorally or extraorally. A datastorage device can be embedded in the appliance. A first microphone canpick up body conduction sound, a second microphone can pick up ambientsound, and a noise canceller can be used to subtract ambient sound fromthe body conduction sound. The actuator transmits sound through a tooth,a maxillary bone, a mandibular bone, or a palatine bone. A linking unitcan provide sound to the transceiver, the linking unit adapted tocommunicate with an external sound source. The transceiver can be awired transceiver or a wireless transceiver.

Advantages of preferred embodiments may include one or more of thefollowing: ease of insertion and removal of the intraoral appliance,comfortable fit, increased safety (e.g., unlikely the user canaccidentally swallow the appliance or have the appliance lodge in theuser's trachea), the ability to eat and drink while wearing theappliance, the ability to wear the appliance for extended periods oftime (e.g., for periods of time exceeding two hours), enhanced safetysuch that the appliance is unlikely to be accidentally swallowed by auser or accidentally lodge in the trachea of a user, a secure fit on atooth or teeth of the user or a tooth or teeth and a portion of anotherpart of the user's dental anatomy such as the gingival tissue or palatewithout the need to adhere or affix the appliance to a portion of saiduser's dental anatomy by dental glue, adhesive, bonding material or thelike, and the lack of any need to modify or alter the dental anatomyincluding any removal of or alteration to any portion of the surface ofa tooth (e.g., grinding, ablation, polishing and the like) or any otherpart of the dental anatomy for insertion or use by the user of theappliance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a perspective top view of an intraoral appliance forconducting sound transmission via bone conduction.

FIG. 1B shows a perspective side view of the appliance of FIG. 1A.

FIG. 1C shows an exemplary mechanical placement of components of eachchamber of FIG. 1A.

FIG. 1D shows an exemplary clam-shell configuration for an intraoralappliance for conducting sound transmission via bone conduction.

FIG. 2 shows a top view of another embodiment of an intraoral appliancefor conducting sound transmission.

FIG. 3 shows a diagram illustrating the coupling of the actuator to oneor more teeth.

FIG. 4A shows an illustrative configuration of the individual componentsin a variation of the oral appliance device having an externaltransmitting assembly with a receiving and transducer assembly withinthe mouth.

FIG. 4B shows an illustrative configuration of another variation of thedevice in which the entire assembly is contained by the oral appliancewithin the user's mouth.

DESCRIPTION

All patents and patent applications cited herein are hereby incorporatedby reference in their entireties.

Various embodiments of the intraoral appliance are described herein anddepicted in the drawings. The advantages of the present invention areseveral and include appliances that are comfortable, facilitate extendedwear, allow for eating and drinking while the appliance is worn by theuser, provide for a secure fit on at least one tooth of the user or, insome embodiments, on at least one tooth and another portion of theuser's dental anatomy such as the gingiva or palate, and do not requireany modification to the dental anatomy including any removal of oralteration to any portion of the surface of a tooth (e.g., grinding,ablation, polishing and the like) or any other part of the dentalanatomy for insertion or use by the user. Moreover, in some embodiments,bonding of the appliance to a tooth or teeth or other portion of thedental anatomy is not required to create a secure fit of the appliancein the mouth of the user as some embodiments inherently possess, byvirtue of their design (e.g., the clamshell design depicted in FIGS. 1Dand 1E), the means for providing a clamping force that facilitates theappliance's secure fit on the tooth or teeth of the user. No furthermeans of affixing the appliance to the user is required.

An exemplary removable intraoral sound transmission appliance is shownin FIG. 1A. The appliance is worn by a user in his or her oral cavity.The appliance includes a power chamber 401 that supplies energy to powerthe appliance. The power chamber 401 includes an energy reservoir 402such as a battery. The battery is charged by charger electronic 403which can receive external energy through inductive coupling or candirectly receive a charge through two terminals. If the charging is tobe done inductively, a recharging coil 404 is also enclosed in the powerchamber 401.

The power chamber 401 provides energy for electronics in an actuationchamber 407. Mechanically, the chambers 401 and 407 are connected by abridge 405. Inside the bridge 405 are cables that supply power to theactuation chamber 407. Other devices such as antenna wires can beembedded in the bridge 405. The chambers 401, 407 and the bridge 405 aremade from human compatible elastomeric materials commonly used in dentalretainers, among others.

Turning now to the actuation chamber 407, an actuator 408 is positionednear the patient's teeth. The actuator 408 is driven by an electronicdriver 409. A wireless transceiver 450 provides sound information to theelectronic driver 409 so that the driver 409 can actuate the actuator408 to cause sound to be generated and conducted to the patient's earthrough bone conduction in one embodiment. For example, the electronicand actuator assembly may receive incoming sounds either directly orthrough a receiver to process and amplify the signals and transmit theprocessed sounds via a vibrating transducer element coupled to a toothor other bone structure, such as the maxillary, mandibular, or palatinebone structure. Other sound transmission techniques in addition to boneconduction can be used and are contemplated by the inventors.

FIG. 1B shows a side perspective view of the appliance of FIG. 1A. Theoral appliance of FIG. 1A may be a custom-made device fabricated througha variety of different process utilizing, e.g., a replicate model of adental structure obtained by any number of methods, as described belowin further detail. The oral appliance may accordingly be created to fit,adhere, or be otherwise disposed upon a portion of the patient'sdentition to maintain the electronics and transducer device against thepatient's dentition securely and comfortably.

FIG. 1C shows a perspective view of the electronics housed by thechambers 401 and 407. In the power chamber 401, the recharging coil 404is positioned at one end and the battery 402 is positioned at the otherend of the chamber 401. The control electronics for the chargingoperation is in a circuit board 420B behind the battery 402 and coil404.

Correspondingly, in the actuation chamber 407, the actuator 408 in turnis made up of a piezoelectric actuator 408B that moves a mass 408A. Thedriver 409 and wireless transceiver circuitry are provided on a circuitboard 420A.

Another exemplary removable intraoral sound transmission appliance 500is shown in FIG. 1D. The appliance includes a first chamber with apiezoelectric transducer 510 which is attached to a housing through aclip. A mass 514 is mechanically connected to the transducer 510. Thetransducer is controlled and powered by a wire that connects the firstchamber to a second chamber that contains an antenna 520. A battery 524provides power to both chambers, and to electronics 528 in the samechamber as well as in the first chamber. The appliance is in a clamshellconfiguration and is placed on only one side of the user's mouth suchthat the appliance contacts at least two surfaces of a tooth or teeth,preferably one or two of the back molars of one side of the user'smouth. The appliance can be placed on the one or two back molars of theupper jaw or lower jaw of the user with the appliance oriented such thatthe wire 520 connecting each chamber of the appliance wraps around theback surface of the back molar of the user and provides the clampingforce for the appliance on the back molar or molars of the user.

FIG. 2 shows a top view of another embodiment of an intraoral appliance.The appliance has a body portion 442 that supports two chambers446A-446B that house the actuator, transceiver, control electronic, andpower supply, among others. Two substantially C-shaped support wires444A and 444B enable the appliance to clip onto the wearer's dental archaround curved regions 448 and to be secured therein. The C-shaped wire444A or 444B provides a spring force to the actuator to keep it securedto the teeth. The wire material can be stainless steel or Nitinol, amongothers.

The inventor has discovered that the intraoral sound transmissionappliance of the present invention when designed with certain specificparameters confers certain advantages with respect to the appliance andto the user as discussed above and immediately below. Specifically, thehousing of the intraoral sound transmission appliance of the presentinvention is comprised of a form factor that is optimized for extendedintra-oral wear to improve user comfort, safety, speech or appearancewithout impediment when wearing the appliance. More specifically, in thepreferred embodiment, the appliance is designed and manufactured so thatit conforms to one or more of the conditions specified in the tablebelow:

TABLE Dimension Specification Effect Observations Buccal SideWidth/Thickness 6 mm or less Comfort, Anything over 6 mm will beuncomfortable since (Buccal to Cheek) eating, the width is larger thanthe natural cavity between bulging of the buccal surface of the teethand the cheek. the cheek Also over an extended period of wear, therubbing of the appliance surface will irritate the tissue therebycausing soreness and tissue damage. Furthermore, this dimension in mostsubjects will cause bulging of the cheek which is cosmeticallyundesirable. Lastly, it will obstruct the natural flow of saliva andfood in the oral cavity. Length (Distal- 20 mm or less Eating andLengths of this dimension over 20 mm is messial) aestheticsaesthetically undesirable since the appliance will be visible in mostsubjects when the subject smiles. Height (occlusal- 15 mm or lessComfort, Anything over 15 mm will be uncomfortable gingival) safety,eating since the height of the appliance if manufactured with adimension greater than 15 mm will be bigger than the anatomical heightof the vestibule. It is highly desirable to limit the height of theappliance and position it mostly on the tooth structure as opposed tothe tissue to prevent tissue damage. In addition, the compliancemismatch between the hard surfaces of the appliance to the tissue maycause discomfort so by limiting the height of the appliance to 15 mm orless the risk of tissue damage and discomfort can be significantlyreduced. Form Surface Comfort, A surface curvature less than 0.5 mm willcause blending safety tissue damage and soreness in most subjectscurvature during extended wear of the appliance due to the 0.5 mm orunnaturally shaped profile. larger Surface Roughness Comfort, Anyroughness index greater than 32 microns will index below safety causetissue damage and soreness in most subjects 32 microns during extendedwear of the appliance because the surface roughness will generate toomuch friction against soft tissues of the subject's mouth. MaterialHydrophobic Comfort, Hydrophilic materials will absorb moisture whichbiocompatible safety in turn makes the device susceptible to bacterialpolymer or growth. Also it will cause mouth dryness and metaldiscomfort. Therefore it is desirable to use biocompatible materialsthat have hydrophobic characteristics such as acrylics, urethane,polyester, polycarbonate in addition to metals such as stainless steel,titanium, nitinol and molybdenum alloys. Lingual Side Width 5 mm or lessComfort, gag If the width of the lingual side of the appliance isreflex, greater than 5 mm, the appliance will stimulate speech the gagreflex and also will cause speech impediment in the user. Furthermore, awidth greater than 5 mm will cause discomfort to the user. Length 30 mmor less Comfort, gag An appliance with a length greater than 30 mmreflex, will increase the probability of stimulating the gag speechreflex in most users and further will disrupt the user's natural speechand intelligibility of speech. Height 25 mm or less Comfort, gag Anappliance with a height greater than 25 mm reflex, will increase theprobability of stimulating the gag speech reflex in most users andfurther will disrupt the user's natural speech and intelligibility ofspeech. Form Winged Comfort, In order to minimize the probability ofstimulating design on Gag reflex, the gag reflex, the disruption of theuser's natural gingival speech speech pattern and intelligibility of thespeech, surface with and overall comfort of the appliance for extendedminimum of 5 wear, the two ends of the appliance were designed degreesangle to minimize the gap between the surface of the to minimizeappliance and palatal curvature. Moreover, the the gap thickness of theappliance at the two ends needs to between the be smaller than thethickness at the center of the appliance and appliance, which results ina wing shape design the palatal optimizing the transition from palate tothe curvature surface of the appliance. Surface Roughness Comfort, Alarger roughness index will cause tissue index below safety damage andsoreness in most users during 32 microns extended wear of the device.Material Hydrophobic Comfort, Hydrophilic materials will absorb moisturewhich biocompatible safety in turn makes the appliance susceptible topolymer or bacterial growth. Also it will cause mouth metal dryness anddiscomfort. Therefore it is desirable to use biocompatible materialsthat have hydrophobic characteristics such as acrylics, urethane,polyester, polycarbonate in addition to metals such as stainless steel,titanium, nitinol and molybdenum alloys. Occlusal Surface No occlusalComfort, Placing any foreign material in the bite path will coverageeating, risk cause discomfort for extended wear. Also, this of TMJ couldpotentially cause TMJ and pain associated with TMJ if the appliance isused while eating. Interproximal Material Provide To stabilize theappliance from distal-messial and Buccal/Lingual filling in theanchorage to occlusal-gingival movement, the inventor has prominenceinterproximal stabilize the discovered that adding material filling inthe contour of the appliance for interproximal contour of the lingualand or buccal lingual and/or functionality, surface of the teethprovides increased anchorage buccal improve to improve comfort whilechewing. surface of the comfort teeth while chewing Distal Spring ShapeThe distal Comfort, gag The wire must be designed to be as close asspring is reflex possible to the distal molar while not interferingcomprised of with the bite of the user, otherwise the appliance a wirethat is can stimulate the gag reflex or damage the tooth adapted to theduring natural mastication. distal of the last molar to avoid occlusalinterference and connect the buccal and lingual components (chambers)Material NiTi, SS, Biocomp and The distal spring connects the twocomponents Plastic material (chambers) of the appliance and at the same(name), strength provides spring force to ensure adequate contactcomposite needed to between the surfaces of the appliance for materialgenerate the anchorage and sound delivery. The spring force basedmaterials suitable for this application are Nitinol, on diameterStainless Steel, Titanium and high strength polymers and/or compositematerial. Diameter Less than Comfort Wire diameter larger than 0.060″may stimulate 0.060″ the gag reflex and induce discomfort in most users.Force 0.5 to 3 Securing the A minimum of 0.5 Newton of force is requiredto Newton force appliance to provide adequate spring force for securingthe ensure appliance to the tooth or teeth and transmitting propersound. A force greater than 3 Newtons will not contact for provide anyadditional benefit but instead will adequate cause discomfort to theuser because of the sound increased squeezing force of the spring on thetransmission tooth. Width Less than 3 mm Comfort and If the width of theappliance in the W shape speech design is greater than 3 mm, it willcause discomfort and speech impediment resulting from displacement ofthe tip of the tongue. Location A strap Comfort and The location of thebridge or strap can between speech significantly impact comfort andspeech and gingival placing it between the gingival margin and up tomargin to 15 mm palatal to the gingival margin provides the 15 mmpalatal optimal balance between comfort and to the gingival minimizationof the disruption of normal speech margin of the caused by the placementof the strap in the upper incisors pathway of the tongue. to connectboth sides of the appliance Contour A Shape Comfort Unless the thicknessof the device is less than .060 custom- inches, the shape of thestrap/bridge should be formed to the fabricated to be custom formed tothe wearer's wearer's dental and palatal anatomy to provide the optimaldental and comfort necessary for extended wear. palatal anatomy any onedimension 16 mm or Risk of One of the safety concerns of an intraoraldevice greater swallowing such as an intraoral sound transmissionappliance the appliance is the potential risk for the user toaccidentally swallow the appliance thereby partially or completelyblocking the esophagus or trachea. To minimize this risk, the x, y, or zdimension of the appliance must be at minimum 16 mm or greater, which isgreater than the diameter of a “clinically normal” esophagus or trachea.At this size, the appliance cannot be swallowed intentionally since thenatural gag reflex will prevent this from happening. In case ofaccidental swallowing (unintentional), this size prevents the appliancefrom entering the esophagus or trachea. Metal Contacts for charging &programming Buccal any surface Safety, Prevents damaging the dentalanatomy by having other than the potential to the metal contact thetooth structure. tooth facing scratch the surface teeth Lingual anysurface Safety, Prevents damaging the dental anatomy by having otherthan the potential to the metal contact the tooth structure. toothfacing scratch the surface teeth Material Gold, Corrosion Safety,biocompatibility with good conduction Platinum or resistance plated Formcounter bore Comfort To ensure that presence of the metal contact is notor spherical felt by the tongue and therefore causing soreness shape anddiscomfort for extended wear.

FIG. 3 shows an exemplary cross-sectional view showing the coupling ofthe sound transducer to one or more teeth 450. In FIG. 3, a mountingunit 452 such as a retainer-like housing is placed over one or moreteeth 450. The mounting unit 452 can also be adhesive or glue or asuitable system to secure the appliance to the teeth 450. An actuator454 rests above support arms or links 452A and 452B which aremechanically connected to the teeth 450.

In one embodiment, the actuator 454 is a piezoelectric transducer madewith PZT. PZT-based compounds (Pb[ZrxTil-x]O3 0<x<1, also lead zirconiumtitanate) are ceramic perovskite materials that develop a voltagedifference across two of its facets when highly compressed. Beingpiezoelectric, it develops a voltage difference across two of its faceswhen compressed (useful for sensor applications), or physically changesshape when an external electric field is applied (useful for actuatorsand the like). The material is also ferroelectric, which means it has aspontaneous electric polarization (electric dipole) which can bereversed in the presence of an electric field. The material features anextremely large dielectric constant at the morphotropic phase boundary(MPB) near x=0.52. These properties make PZT-based compounds one of themost prominent and useful electroceramics.

The actuator 454 is also connected to a mass 458 through a mass arm 456.In one embodiment, the actuator 454 uses PZT in a rectangular beambender configuration. The mass 458 can be a tungsten material or anysuitable weight such as the battery or control electronics, amongothers. The support arms or links 452A-452B as well as the mass arm 456are preferably made from ceramic or alumina which enables acoustic orsound energy to be efficiently transmitted by the mounting unit 454.

The appliance can be a custom oral device. The sound source unit cancontain a short-range transceiver that is protocol compatible with thelinking unit. For example, the sound source can have a Bluetoothtransceiver that communicates with the Bluetooth transceiver linkingunit in the appliance. The appliance can then receive the datatransmitted over the Bluetooth protocol and drive a bone conductiontransducer to render or transmit sound to the user.

The appliance can have a microphone embedded therein. The microphone canbe an intraoral microphone or an extraoral microphone. For cellulartelephones and other telephones, a second microphone can be used tocancel environmental noise and transmit a user's voice to the telephone.A noise canceller receives signals from the microphones and cancelsambient noise to provide a clean sound capture.

The appliance can have another microphone to pick up ambient sound. Themicrophone can be an intraoral microphone or an extraoral microphone. Inone embodiment, the microphone cancels environmental noise and transmitsa user's voice to the remote station. This embodiment provides theability to cancel environmental noises while transmitting subject's ownvoice to the actuator 432. As the microphone is in a fixed location(compared to ordinary wireless communication devices) and very close touser's own voice, the system can handle environmental noise reductionthat is important in working in high noise areas.

The system couples microphones and voicing activity sensors to a signalprocessor. The processor executes a detection algorithm, and a denoisingcode to minimize background acoustic noise. Two microphones can be used,with one microphone being the bone conduction microphone and one whichis considered the “signal” microphone. The second microphone capturesair noise or ambient noise, whose signal is filtered and subtracted fromthe signal in the first microphone. In one embodiment, the system runsan array algorithm for speech detection that uses the difference infrequency content between two microphones to calculate a relationshipbetween the signals of the two microphones. As known in the art anddiscussed in U.S. Pat. No. 7,246,058, the content of which isincorporated by reference, this embodiment can cancel noise withoutrequiring a specific orientation of the array with respect to thesignal.

In another embodiment, the appliance can be attached, adhered, orotherwise embedded into or upon a removable oral appliance or other oraldevice to form a medical tag containing patient identifiableinformation. Such an oral appliance may be a custom-made devicefabricated from a thermal forming process utilizing a replicate model ofa dental structure obtained by conventional dental impression methods.The electronic and transducer assembly may receive incoming soundseither directly or through a receiver to process and amplify the signalsand transmit the processed sounds via a vibrating transducer elementcoupled to a tooth or other bone structure, such as the maxillary,mandibular, or palatine bone structure.

In yet another embodiment, microphones can be place on each side of theears to provide noise cancellation, optimal sound localization anddirectionality. The microphones can be placed inside or outside theears. For example, the microphones can be placed either at the openingor directly with the user's ear canals. Each of the systems includes abattery, a signal processor, a transmitter, all of which can bepositioned in a housing that clips onto the ear which, rests behind theear between the pinna and the skull, or alternatively can be positionedin the ear's concha. The transmitter is connected to a wire/antenna thatin turn is connected to the microphone. Each transmitter transmitsinformation to a receiver that activates a transducer that is powered bya battery. Each side of the head can have one set of receiver,transducer and battery. This embodiment provides a bone conductionhearing aid device with dual externally located microphones that areplaced at the entrance to or in the ear canals and an oral appliancecontaining dual transducers in communication with each other. The devicewill allow the user to enjoy the most natural sound input due to thelocation of the microphone which takes advantage of the pinna foroptimal sound localization (and directionality).

In another embodiment, the microphones receive sound signals from bothsides of the head, processes those signals to send a signal to thetransducer on the side of the head where the sound is perceived by themicrophone to be at a higher sound level. A phase-shifted signal is sentto the transducer on the opposite side of the head. These sounds willthen “add” in the cochlea where the sound is louder and “cancel” on theopposite cochlea providing the user with the perception ofdirectionality of the sound.

In yet another embodiment, the microphone at the first ear receivessound signals from the first side of the head, processes those signal tosend a signal to the transducer on that same or first side of the oralappliance. A second microphone at the second ear receives a sound signalthat is lower in amplitude and delayed in respect to the sound sensed bythe first microphone due to head shadowing and physical separation ofthe microphones, and sends a corresponding signal to the secondtransducer on the second side of the oral appliance. The sound signalsfrom the transducers will be perceived by each cochlea on each side ofthe head as being different in amplitude and phase, which will result inthe perception of directionality by the user.

In one embodiment where the microphone is mounted in the user's earcanal, components such as the battery, the signal processor, and thetransmitter can either be located behind the ear or within the folds ofthe pinna. The human auricle is an almost rudimentary, usually immobileshell that lies close to the side of the head with a thin plate ofyellow fibrocartilage covered by closely adherent skin. The cartilage ismolded into clearly defined hollows, ridges, and furrows that form anirregular, shallow funnel. The deepest depression, which leads directlyto the external auditory canal, or acoustic meatus, is called theconcha. It is partly covered by two small projections, the tongueliketragus in front and the antitragus behind. Above the tragus a prominentridge, the helix, arises from the floor of the concha and continues asthe incurved rim of the upper portion of the auricle. An inner,concentric ridge, the antihelix, surrounds the concha and is separatedfrom the helix by a furrow, the scapha, also called the fossa of thehelix. The lobule, the fleshy lower part of the auricle, is the onlyarea of the outer ear that contains no cartilage. The auricle also hasseveral small rudimentary muscles, which fasten it to the skull andscalp. In most individuals these muscles do not function, although somepersons can voluntarily activate them to produce limited movements. Theexternal auditory canal is a slightly curved tube that extends inwardfrom the floor of the concha and ends blindly at the tympanic membrane.In its outer third the wall of the canal consists of cartilage; in itsinner two-thirds, of bone. The anthelix (antihelix) is a folded “Y”shaped part of the ear. The antitragus is the lower cartilaginous edgeof the conchal bowl just above the fleshy lobule of the ear. Themicrophone is connected with the transmitter through the wire andantenna. The placement of the microphone inside the ear canal providesthe user with the most natural sound input due to the location of themicrophone which takes advantage of the pinna for optimal soundlocalization (and directionality) when the sounds are transmitted to thecochlea using a straight signal and “phase-shifted” signal to applydirectionality to the patient. High quality sound input is captured byplacing the microphones within or at the entrance of the ear canal whichwould allow the patient to use the sound reflectivity of the pinna aswell as improved sound directionality due to the microphone placement.The arrangement avoids the need to separate the microphone and speakerto reduce the chance of feedback and allows placement of the microphoneto take advantage of the sound reflectivity of the pinna. The systemalso allows for better sound directionality due to the two boneconduction transducers being in electrical contact with each other. Withthe processing of the signals prior to being sent to the transducers andthe transducers able to communicate with each other, the system providesthe best sound localization possible.

The appliance can include a data storage device such as a solid statememory or a flash storage device. The content of the data storage devicecan be encrypted for security. The linking unit can transmit encrypteddata for secure transmission if desired.

The appliance may be fabricated from various polymeric or a combinationof polymeric and metallic materials using any number of methods, such ascomputer-aided machining processes using computer numerical control(CNC) systems or three-dimensional printing processes, e.g.,stereolithography apparatus (SLA), selective laser sintering (SLS),and/or other similar processes utilizing three-dimensional geometry ofthe patient's dentition, which may be obtained via any number oftechniques. Such techniques may include use of scanned dentition usingintra-oral scanners such as laser, white light, ultrasound, mechanicalthree-dimensional touch scanners, magnetic resonance imaging (MRI),computed tomography (CT), other optical methods, etc.

In forming the removable oral appliance, the appliance may be optionallyformed such that it is molded to fit over the dentition and at least aportion of the adjacent gingival tissue to inhibit the entry of food,fluids, and other debris into the oral appliance and between thetransducer assembly and tooth surface. Moreover, the greater surfacearea of the oral appliance may facilitate the placement andconfiguration of the assembly onto the appliance.

Additionally, the removable oral appliance may be optionally fabricatedto have a shrinkage factor such that when placed onto the dentition,oral appliance may be configured to securely grab onto the tooth orteeth as the appliance may have a resulting size slightly smaller thanthe scanned tooth or teeth upon which the appliance was formed. Thefitting may result in a secure interference fit between the applianceand underlying dentition.

In one variation, an extra-buccal transmitter assembly located outsidethe patient's mouth may be utilized to receive auditory signals forprocessing and transmission via a wireless signal to the electronicsand/or transducer assembly positioned within the patient's mouth, whichmay then process and transmit the processed auditory signals viavibratory conductance to the underlying tooth and consequently to thepatient's inner ear. The transmitter assembly, as described in furtherdetail below, may contain a microphone assembly as well as a transmitterassembly and may be configured in any number of shapes and forms worn bythe user, such as a watch, necklace, lapel, phone, belt-mounted device,etc.

FIG. 4A illustrates a schematic representation of one variation oftwo-way communication assembly 14 utilizing an extra-buccal transmitterassembly 22, which may generally comprise microphone 30 for receivingsounds and which is electrically connected to processor 32 forprocessing the auditory signals. Processor 32 may be connectedelectrically to transmitter 34 for transmitting the processed signals tothe electronics and/or transducer assembly 16 disposed upon or adjacentto the user's teeth. The microphone 30 and processor 32 may beconfigured to detect and process auditory signals in any practicablerange, but may be configured in one variation to detect auditory signalsranging from, e.g., 250 Hertz to 20,000 Hertz.

With respect to microphone 30, a variety of various microphone systemsmay be utilized. For instance, microphone 30 may be a digital, analog,and/or directional type microphone. Such various types of microphonesmay be interchangeably configured to be utilized with the assembly, ifso desired.

Power supply 36 may be connected to each of the components intransmitter assembly 22 to provide power thereto. The transmittersignals 24 may be in any wireless form utilizing, e.g., radio frequency,ultrasound, microwave, Blue Tooth® (BLUETOOTH SIG, INC., Bellevue,Wash.), etc. for transmission to assembly 16. Assembly 22 may alsooptionally include one or more input controls 28 that a user maymanipulate to adjust various acoustic parameters of the electronicsand/or transducer assembly 16, such as acoustic focusing, volumecontrol, filtration, muting, frequency optimization, sound adjustments,and tone adjustments, etc.

The signals transmitted 24 by transmitter 34 may be received byelectronics and/or transducer assembly 16 via receiver 38, which may beconnected to an internal processor for additional processing of thereceived signals. The received signals may be communicated to transducer40, which may vibrate correspondingly against a surface of the tooth toconduct the vibratory signals through the tooth and bone andsubsequently to the middle ear to facilitate hearing of the user.Transducer 40 may be configured as any number of different vibratorymechanisms. For instance, in one variation, transducer 40 may be anelectromagnetically actuated transducer. In other variations, transducer40 may be in the form of a piezoelectric crystal having a range ofvibratory frequencies, e.g., between 250 to 4000 Hz.

Power supply 42 may also be included with assembly 16 to provide powerto the receiver, transducer, and/or processor, if also included.Although power supply 42 may be a simple battery, replaceable orpermanent, other variations may include a power supply 42 which ischarged by inductance via an external charger. Additionally, powersupply 42 may alternatively be charged via direct coupling to analternating current (AC) or direct current (DC) source. Other variationsmay include a power supply 42 which is charged via a mechanicalmechanism, such as an internal pendulum or slidable electricalinductance charger as known in the art, which is actuated via, e.g.,motions of the jaw and/or movement for translating the mechanical motioninto stored electrical energy for charging power supply 42.

In another variation of assembly 16, rather than utilizing anextra-buccal transmitter, two-way communication assembly 50 may beconfigured as an independent assembly contained entirely within theuser's mouth, as shown in FIG. 4B. Accordingly, assembly 50 may includean internal microphone 52 in communication with an on-board processor54. Internal microphone 52 may comprise any number of different types ofmicrophones, as described above. Processor 54 may be used to process anyreceived auditory signals for filtering and/or amplifying the signalsand transmitting them to transducer 56, which is in vibratory contactagainst the tooth surface. Power supply 58, as described above, may alsobe included within assembly 50 for providing power to each of thecomponents of assembly 50 as necessary.

In yet other variations, vibrations may be transmitted directly into theunderlying bone or tissue structures rather than transmitting directlythrough the tooth or teeth of the user.

For any of the variations described above, they may be utilized as asingle device or in combination with any other variation herein, aspracticable, to achieve the desired hearing level in the user. Moreover,more than one oral appliance device and electronics and/or transducerassemblies may be utilized at any one time.

Moreover, each of the different transducers can also be programmed tovibrate in a manner which indicates the directionality of sound receivedby the microphone worn by the user. For example, different transducerspositioned at different locations within the user's mouth can vibrate ina specified manner by providing sound or vibrational queues to informthe user which direction a sound was detected relative to an orientationof the user. For instance, a first transducer located, e.g., on a user'sleft tooth, can be programmed to vibrate for sound detected originatingfrom the user's left side. Similarly, a second transducer located, e.g.,on a user's right tooth, can be programmed to vibrate for sound detectedoriginating from the user's right side. Other variations and queues maybe utilized as these examples are intended to be illustrative ofpotential variations.

In variations where the one or more microphones are positioned inintra-buccal locations, the microphone may be integrated directly intothe electronics and/or transducer assembly, as described above. However,in additional variation, the microphone unit may be positioned at adistance from the transducer assemblies to minimize feedback.

Modification of the above-described embodiments of the intraoralappliance and methods for carrying out the invention, combinationsbetween different variations as practicable, and variations of aspectsof the invention that are obvious to those of skill in the art areintended to be within the scope of the claims.

What is claimed is:
 1. An intraoral appliance for sound transmissioncomprising an intra-oral bone conduction sound transmission devicesecurable to one or more teeth via an interference fit between thedevice and the one or more teeth.